AP Chem Reaction Predictions Are Back





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Discus: SAT/ACT Tests and Test Preparation: April 2004 Archive: AP Chem Reaction Predictions Are Back
By Scion (Scion) on Saturday, April 24, 2004 - 02:33 am: Edit

give these a shot:

H2SO4(dilute)+BaCl2(soluble)

Al2O3(solid)+NaOH(strong base=soluble)

NH3+HF

By Kewlkiwi102 (Kewlkiwi102) on Saturday, April 24, 2004 - 10:34 am: Edit

For the first one maybe -->2HCl(aq)+BaSO4(s)

I hate these, its probably totally wrong. :)

By Hiamerica (Hiamerica) on Saturday, April 24, 2004 - 12:50 pm: Edit

BaSO4 + H+ + Cl- since it is a strong acid
Na2O + Al(OH)3
NH4F
do post the answers scion.

By Kewlkiwi102 (Kewlkiwi102) on Saturday, April 24, 2004 - 12:55 pm: Edit

Hm...I thought that the 2nd one would be something like
-->Al(OH)3 + O2 + Na+

I dunno about Na2O becuase you never really hear about O-2 in solution (which it would be becuase Na+ is always soluable...)

By Scion (Scion) on Saturday, April 24, 2004 - 01:59 pm: Edit

for the first one, is it really BaSO4, cuz doesnt H2SO4 dissociate into H+ and HSO4? if Ba combines w/ HSO4, how would it be BaSO4? i dont have the answers yet, but i will get them to u ASAP. thanks for helping guys.

never mind what i just said about H2SO4. i forgot that it COMPLETELY dissociates into 2H+ and SO4 (right???) haha

By Frozentears801 (Frozentears801) on Saturday, April 24, 2004 - 06:45 pm: Edit

HSO4- is considered a weak acid, but its Ka is actually quite high. As the barium consumes the sulfate and precipitates, the dissociation of HSO4- is pushed to the right until all of it has been consumed, or until all of the barium has been consumed.

By Anduin (Anduin) on Saturday, April 24, 2004 - 07:50 pm: Edit

The first is SO4 2+ + Ba 2- BaSO4.

What do the sodium and oxide ions do in the second one?

By Blee731 (Blee731) on Saturday, April 24, 2004 - 08:40 pm: Edit

1) Ba +2 + SO4 -2 --> Ba(SO4)
2) Al203 + OH -1 -->Al + H20
3) NH3 + HF --> NH4 + F2

By Frozentears801 (Frozentears801) on Sunday, April 25, 2004 - 06:25 pm: Edit

Blee731, I don't think #2 has the results Al and H20... Al2O3 is a metal oxide, which is a base. I don't think bases react with bases, so I think perhaps the hydroxide complexes the aluminum. But does O2 form? that seems to be probable, too, because O2- is such a strong base in water that it would immediately form OH- ions. Which leads to the coordination compound Al(OH)4. Hm. I'm perplexed.

By Kewlkiwi102 (Kewlkiwi102) on Sunday, April 25, 2004 - 06:37 pm: Edit

I think you meant Al(OH)3...

Looking at these again, I think that that one would be Al+3 + OH- --> AL(OH)3
W/ Na+ and O-2 being spectators.
Where are these probs from btw?

By Maverick27 (Maverick27) on Sunday, April 25, 2004 - 07:56 pm: Edit

i agree with u all on #1
#2 i think its Al2O3 + OH- --> Al(OH)3 + O2
#3 i think its NH3+HF --> NH4+ + F-
thoughts?

By Maverick27 (Maverick27) on Sunday, April 25, 2004 - 08:41 pm: Edit

wait, do you write weak acids in dissociated form? no right, only strong acids?

By Kewlkiwi102 (Kewlkiwi102) on Sunday, April 25, 2004 - 08:57 pm: Edit

yep you have it right about the weak/strong acid thing maverick27.

Does anyone think the AP is going to be easy? Im actually not too concerned....should I be?


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